Improvement in grinding and grist mills



W. SPRAGTJ'E.

. GRINDING AND GRIST-MILLS.

No.175,30'6. Patented March 28,1876.

Jagf 6 UNITED/STATES,

PA ENT OFFICE.

WILLIAM SPRAGUE, OF PHILADELPHIA, PENNsYLvAmA, ASSIGNOR 0F ONE-HALF HIS ErcHr TO oHAELEs ENEU JOHNSON, 0F sAME PLAoE- IMPRZDVEMENLTI'N GRINDING AND GRIST'MILLS.

Specification forming part of Letters Patent N 0. 1 75,306, dated March 28, 1876; application filed December 17, 1875.

To all whom it may concern Be it known that I, WILLIAM SPRAGUE, of the city and county of Philadelphia, State of Pennsylvania, have invented a new and useful Improvement in Grinding and Grist Mills, which improvement is fully set forth in the following specification, reference being had to the accompanying drawings.

Like letters indicate like parts.

The object of my invention is to increase the capacity of the mills by means of a faster motion, and forcing the material to be ground into the mill.

I am aware that this has been used before, but not in the manner that I propose to use it, the difference being not only in the mode of forcing the material into the mill, but also in the manner of grinding and the form of the grinding-plates, as will be seen in the following description.

Figure l is a front elevation, partly sectioned. Fig. 2 is a plan of the lower half of easing a a, showing plates 0 and b, with hopper 6.

a a is an iron casing inclosing the two grinding plates or disks b and c. From the upper side of the plate b is a hollow shaft, d d, surmounted by a. globe-shaped hopper, e, being hollow and circular in form inside as well as outside. On the upper side is an opening e, somewhat smaller than the diameter of the globe, and on the lower side the opening through shaft 01 d. It will be seen that, owing to the great centrifugal force caused by the speed of plate b, shaft (1, and hopper e, the material to be ground has a tendency to rise up within the hopper until'it reaches a certain point above the center of the globe, (which is determined by the speed of the mill,) when the material, owing to the sides of the globe curving in toward the center of the opening 0, falls within the globe, over the opening of the shafts d d. This operation is furthermore aided by the support of spiral y at 9, being slightly angular, thus not only tending to force the material down between the plates b and 0, but also to a certain extent to mix various ingredients. From the side of easing at f is fastened a support, g g, for the spiral 3 which runs down through the hollow shaft d d. This spiral is stationary, whereas the hopper c, hollow shaft 01 d, and plate b revolve, and, in doing so, by meansof the centrifu gal force causing the material to revolve against the spiral 3 thereby forcing the article to be ground down between the plates b and c.

h is a scraper with handle h, and has a spring to force the scraper it against plates b and c, for the purpose of keeping the edges of the plates b and c from clogging, which would prevent the material, after it is ground, from escaping to the lower side of or below plate 0, where there are scrapers t' 13 t iattached to the lower side of the plate 0, to carry off the ground material to the outlet J. From the lower side of plate 0 is a hollow shaft, K K, revolving in .a bearing, L L, forming partof the casing a a. Within the hollow shaft K K is a steel center, m, resting on an adjusting-rest, n, the said rest being raised or lowered by means of a hand-wheel, 0o,having its center threaded to fit the screw on lower part of rest a. By this means the, fineness of the material to be ground may be regulated. The motion to the plates b and c is given by means of a series of bevel and gear wheels, as shown in Fig. l. The power or driving shaft 10, with bevel-wheels r r, revolves the shaft 8,

and gear-wheels u and 'u, which in turn propel their corresponding pinion-wheels V and V, or plates b and c.

It will be noticed that the plates b and c revolve in the same direction, but, owing to the unequal diameters of the gear-wheels u and u and V V, at different speeds, the object of which is to facilitate feeding the material to be ground, and which is necessary, owing to the rapid rate of speed at which the mill will be run. 7

I do not confine myself to metal faces of plates b and c, as the same may be covered by such material as may be most suitable for the grinding of different articles; nor do I confine myself to the eccentric form of plate b, as the same may be made with the center of its revolution the center of the plate or disk b, thereby accomplishing the same result.

What 1 claim as my invention is- "combination with shaft 11 d, and with or with- 1. The combination of the eccentric grind 4. In combination with plates 3) and c, shafts ing-plate b with plate a, hollow shaft (1 d, and d d and K K, the pinions V V, gear-wheels u casing a, as described, and above set forth. u, beveled gear-wheels r r, and pulley W, as

2. The rotating globe'shaped hopper e, in above described, and for the purpose set forth.

out the stationary spiral feeder y, as described, WILLIAM SPRAG UE. and for the purpose set forth.

3. In combination with rotating grindingpl-ates b and c, the scraper it placed at the edges thereof, as shown and described.

Witnesses:

HERBERT M. FULLER, ALLEN J. FULLER. 

